Grinding wheels with inserted tubular abrasive elements



April 21, 1959 w. OSENBERG GRINDING WHEELS WITH INSERTED TUBULAR ABRASIVE ELEMENTS 5 Sheets-Sheet 1 Filed April 4, 1957 A'Hvs //v VENTOR.

w. OSENBE'RG a J LII? April 21, 1959 w, OSENBERG 2,882,655

GRINDING WHEELS WITH INSERTED TUBULAR ABRASIVE ELEMENTS Filed April 4, 1957 3 Sheets-Sheet 2 F ig./3

v v. W OS N RG, INVENTOR.

-' am I 2,882,655 GRINDING WHEELS WITH INSERTED TUBULAR ABRASIVE ELEMENTS Filed April 4, 1957 April 21, 1959 w. OSENBERG 3 Sheets-Sheet 3 OSENBERG INVENTOR.

w ,wmmi

WHEELS WITH INSERTED TUBULAR ABRASIVE ELEMENTS Werner Osenberg, Hindenburg-Allee, Gehrden, Germany, assignor to Bisterfeld & Stolting, Radevormwald (Rhineland), Germany Application April 4, 1957, Serial No. 650,740

GRINDING Claims priority, application Germany April 7, 1956 4 Claims. (Cl. 51-209) This invention relates to a further development of flexresisting bond composed of thermosetting synthetic resin.

Grinding tools have already been proposed whichpossess the geometrical shape of hollow cylinders with parallel side walls. different diameters and arranged one within the other concentrically on a carrier disc. Grinding tools constructed in this manner must run at a very high working speed because the wear when working solid and hard materials increases as the working speed decreases. An increase in the working speed beyond 90 metres per second is limited by the strength of the abrasive tubes wound from fabric webs. The wall thickness of these tubes, and especially the flange height, that is the effective abrasion height of the abrasive body forming the multiple-cup disc or wheel, must not exceed a certain measurement because, by increasing the efiort arm on which the centrifugal forces act, the speed of rotation at which the abrasive ring will burst is reduced. The multiple-step grinding rings (multiple cup discs), owing to these limits, only enable relatively small quantities of material to be ground down completely and are primarily suitable for lighter work, for example for sharpening tools, grinding.

work with small machiningallowance, and so forth.

In order to remove greater quantities of chips, for example when grinding the heads of railway rails, the surface of tubes and the like, it has also been proposed to use multi-step segments which have a relatively large curvature radius. To avoid undue unbalance, the individual segment shells must be pressed with relatively great precision. When the segments have been placed in a grinding wheel this must be balanced.

In order to remove the above-mentioned limits to the employment of the abrasive bodies which have already been proposed, it is proposed according to the present invention to use, instead of the multi-step grinding rings of relatively large diameter and the multi-step segment bodies, tubes preferably wound from fabric webs and of small diameter with a heat-resistant bond composed of thermosetting synthetic resin, the length of these tubes being many times greater than their outer diameter, the tubes being arranged adjustable in longitudinal direction, axially, radially or at anincline to the axis of rotation of a metal carrier (grinding wheel) To work surfaces of relatively large area, for example the surface of metal sheets, grinding rolls can be employed. Abrasive tube sections are slipped on to bolts radially fixed in rings by pinning, by internal clamping devices or the like. By assembling such rings. set with four to six abrasive tube sections, grinding rolls can be formed the width of which is variable, so that they can be adapted to the surface to be worked. As the width of ..these rings corresponds to the internal diameter of the .abrasive tube sections, the, paths produced during 'the grinding'operation overlap so that no steps are formed on the surface of the workpiece. It is ,evidentthat the.

These abrasive cylinders can be of- 2,882,655 Patented Apr. 21, 19.59

2 whole grinding roll may be profiled by suitably shaping the individual abrasive tube sections.

ible grinding tools of hollow cylindrical shape with heat web-wound and compressed abrasive tubes. sections may be of any shape, for example circular, rec- For internally working, for example tubes, the abrasive tube sections can also be fitted in levers which spread under the action of centrifugal force and are hingedly connected with a shaft rotating at a high speed. The internal working of bores is naturally also possible with grinding rolls, the abrasive tube sections of which are preferably radially adjustable and readjustable, for example by the axial displacement of a mandrel within the roll.

,' grinding performances, due on the one hand to the existing bore, that is the existing free space and the thin wall thickness which does not prevent the leading 0E of the chipsproduced by the grinding operation, and on the other hand to the high Working speed possible when using The crosstangular, hexagonal and so forth; they may also be in the form of ring sections which, when fitted together, produce a circular path. If a plurality of such circular paths were to be arranged concentrically to each other,

' the abrasive tubes having the cross-section of one ring section are provided with spacers. The cross-section of the tubes should be so dimensioned that a sufficient quantity of abrasive material with corresponding cutting capacity can be accommodated.

With a view toproducing greater abrasive tube volume increasing the chip removing capacity, the free crosssectional area of grinding tubes of any shape can be additionally reduced by introducing more abrasive bodies. Care must, however, be taken that there is suificient free space for leading off the larger quantities of chips produced. The additional abrasive bodies introduced can be rigidly connected with the outer abrasive tubes by welding, sticking or the like.

By means of wear-proof spacers, adjustable in relation to the surface engaged by the grinding tools, it is possible, as these spacers are in continual contact with the surface of the workpiece, for the end face of the tubular grinding tool to bear only lightly in relation to the unbroken, flat or concave surface, for example the inner wall of a tube, with the result that the wear of the abrasive tubes is considerably reduced. The wear-proof spacers can serve at the same time as means for measuring during the grinding operation.

Several embodiments of the invention are illustrated by way of example in the accompanying drawings, in which:

Figure 1 is a cross-sectional view through a tubular grinding tool having embedded therein abrasive bodies.

Figure 2 is a diagrammatic view showing how two concentric grinding elements are secured together.

Figure 3 is a similar view showing a modification.

Figure 4 is a similar view illustrating a further modification.

Figure 5 is a similar view with parts in cross-section illustrating a still further modification.

Figure 6 is a view similar to Figure 2 showing a still further modification.

Figs. 7 and 8 are top plan and cross-sectional (diagrammatic) views respectively of a grinding device in which I tubular abrasive bodies are fitted in a carrier parallel figure, it is evident that a greater number of grinding tubes can be fitted in-the carrier 5. If the holders for the tubular grinding bodies 1, shown in Fig. 10, are slidable in a radial guide 9, the diameter of the pitch circle of the grinding tubes 1 can be varied by the radial displacement of these grinding tubes by means of fiat spirals 13 worked in a ring 12 rotatable in relation to the carrier 5. The holders 10 are connected with the flat spirals 13 through the intermediary of intermediate members 11. If the tubular grinding bodies are of relatively great length, two rings 12 and two flat spirals 13 are provided in the carrier 5, which for this purpose is made of cylindrical shape, so that the holders provided for the front and rear ends of the tubes, as well as the grinding tubes fitted therein, carry out a radial parallel displacement in relation to the axis of rotation of the carrier 5.

In addition to the axially parallel and inclined arrangements of the tubular grinding bodies 1 according to Figs.

7 to 9, grinding tube sections may be employed arranged as shown in Fig. 11, so that they can be fitted on pins 14 connected to the carrier ring 5 by means of a screw-threaded extension 15. The grinding tube sections 1 can be fixed on the pins 14 by means of transverse pins, by known internal clamping devices or by providing the pin 14 and also the bore of the grinding tube sections 1 with screw threads. The carrier ring 5 has a bore 7 and rotates about the central axis shown in Fig. 11. By profiling the guiding tube sections 1 fitted on the pins 15 it is possible to surface-grind workpieces having a certain, for example, curved profile.

If bores, for example the inner wall 21 of a cylinder 20, are to be ground, the grinding tube sections 1 may, according to Fig. 12, be mounted on-two or more onearmed levers 18 and 19, which are connected by a hinge 17 with the rotary driving shaft 16 running at a high speed, so that, during the rotation, the grinding tube sections 1 are pressed by the centrifugal effect in the direction of the arrows against the tube wall. During the grinding of the wall 21 of a tube having a diameter D, the whole grinding wheel must carry out a feed movement in the direction of the arrow S. As hereinafter set forth in the description of Figs. 24 and 25, the internal grinding of tubes can also be carried out with grinding rolls which can likewise be varied as regards their effective diameter.

In Figs. 13 to 17 a construction for grinding the outer wall of tubes is shown by way of example as an embodiment of the invention. Seeing that in this case large quantities of material have to be removed, it is necessary to employ tubular grinding bodies of great length. These tubes 1 having an initial length of 1 metre and more, are placed in a cylindrical grinding construct on (Fig. 13) which consists substantially of the following parts: The outer casing 23 made from very resistant steel, the carrier tube 27, the four spacers 28 for establishmg a firm connection between 23 and 27, covers 25 and 26 fitted in the ends, the shaft centrally arranged in the construction and which does not participate in the rotation, the roller bearings 34, the pillow blocks 36 which are bolted to the sliding carriage 39 and the supports 24 rigidly connected with the outer casing 23 and serving as bearing surface for the grinding tubes I acted upon by centrifugal force (see also Fig. 15).

The tubular grinding bodies 1 arranged in groups of three (in Figs. 14 to 17), are secured to a cross-piece 42 by means of screws 43, which cross-piece is guided on the carrier tube 27, the spacers 28 and the profile of the support 24 facing the axis of rotation (see Figs. 13 and 16).

According to Fig. 17, the cylindrical members 29 are inserted in the grinding tubes 1 so that they can be secured by screwing. Each four groups of grinding bodies are fitted in the grinding construction according to Figs.

13 and 14. With the aid of screwspindles 30-, carrying pins 31 at both ends, and of an epicyclic gear 32/33, the tubular grinding bodies 1 can, on being simultaneously and uniformly turned in the construction, be shifted in axial direction and so adjusted that a small portion of the grinding bodies 1 projects from the cover 25 facing the tube 38 to be ground. For grinding the cylindrical outer wall or jacket of tubes the working surfaces 22 of the tubular grinding bodies 1 are so profiled that a larger surface of the bodies 1 contacts the outer wall or jacket of the tube 38 to be ground. As continuous wear takes place during the grinding operation, the tubular bodies must be periodically ,or continuously readjusted by means of the constructional elements 30, 32, 33 and 42. In the case of periodic displacement of the bodies 1, the feeding movement must be effected by the carriage 39 carrying the construction and which can be coupled with a precision spindle.

The amount of adjustment of the grinding construction according to Fig. 13 in relation to the horizontal central axis of the tube 38 to be surface ground, must be effected in such a manner that the greatest effective diameter of the tubular grinding body 1 is located in the middle. The grinding construction can be driven by means of a belt 37. The speed must be such that the grinding tools I operate at an average working speed of metres per second.

The grinding device 5 with vertically arranged grinding spindle 52 illustrated in Fig. 23, has a relatively large number of axially parallel bores 63 of the same pitch circle diameter, in which bores the tubular grinding bodies 1 are inserted by hand. The grinding spindle 53 is held, for example, in the arm 62 of the grinding machine by clamping. The tubes I inserted by hand are allowed to rest on the surface 22 to be ground when the machine is at a standstill and are then clamped, for example, by means of hydraulically operating pressure means built up in the following manner:

A piston 57 arranged radially in front of each grinding tool 1 can be moved by pressure fluid which is fed via the passages 58, 60 and 61. The annular recess 58 turned in the grinding device 5 is closed by means of a screw ring 59. The centrifugal forces occurring at the speed of rotation necessary for the grinding device 5 also produce an amply tight seating of the tubes 1 inserted by hand. The surfaces of the bore 63 against which the grinding tools 1 are pressed by centrifugal effect are preferably provided with transverse grooves, screw threads, roughened surfaces and the like, and similarly a portion of the outer wall of the tubular grinding tools. With this type of holding means for the grinding tools 1 a slight stress, for example spring pressure, is sufficient once the tools have been inserted in the carrier 5. For fixing the grinding tubes 1 in the grinding device 5 any of the known clamping arrangements can be employed, including those using plastic agents, such as neoprene.

The grinding device is mounted on a conical pin 54 formed on the grinding spindle 53 and there held by means of screw 55 with interposed washer 56.

The spaces 63 for receiving the tubular grinding tools 1 may be of any desired cross-sectional shape, for example also for taking those having the cross-sectional shape of circular ring segments or sections such as those shown in Figs-20 and 22.

For the economical chip removal of large volumes of material, for example when surface grinding metal sheets, as shown on the right-hand side of Fig. 23, provided it is a question of unbroken surfaces from which the grinding device is not raised during the grinding operation, cartridges enclosed in thin, easily worn away casings 69 and filled with accurately dosed quantities of loose abrasive grit 68 are inserted in the tubular grinding bodies and pressed under elastic pressure against the surface 22 to be ground, for example by means of an air cushion 7 ortbag-Jtl whichrcantbersupportenabysaa-dtscfll fixed=by a;

crossepinifik Akyalve 72;ensuresethati:a certaimpressure:

issmaintainedeim-theibagflm Atsthe beginningwfethe grinding-operation, .therportionof-. the-;thin .-casing ;of#the:cartridge facinggthezsurfacewofz the workpieceewillmatnrallyvbe rnhbed-.;away,: so that. the abrasivegritr69risrexposedt and: becomes effective; These abrasive grit cartridges mayralso .be ofanypdesired: crosssectional shape; so.--that.they:-cair likewise beintroduced intonthe .freecross-sectional.Espaces inthe grinding tubes 1,-. as;shown, for-example,.inrFig-.; 20. The abrasive grit ofetheacartridgessmayg as already; mentioned inathe intro dnetion to: .-the.1 specification.- \be-. held. in. lightbond: by various means to :enable:- thegrinding device to be; if: necessary,- lifted :ofir-thesurface of the-workpiece during the'egr inding operationr Whereassthe grindin'g; device -,shown-.in Fig, 11 has a. carrier ring which is wider tharrathe largest diameter- Of-nthQi grinding ftubesectionstl slipped on to the plugs on pins 14;-,the-carrier. rings S Yof the construction 'illustrated in Figs.-.24 and iare only of awidthcorresponding to'1he-internal-.-diameterxofthe grinding: tube sections 1. Also [in sthis-.case'- theselatterfare slippedon .torthe pins or-Tp1ugsj-.-14 which are screwed into I the carrier ring 5 bygmeans .of screw-threaded extensions- 15 or are made integ galwtherewith Thebodies-1 maybe fixed on the pins 14 by cross-pins 66, by an internal clamping arrange ment not :shown ion:- the drawing, or by screwthreads which would; have to be .provided'on thepins 14 and-in therbores of the 'bodies 1. Owing to the narrow width of-cthe 5 rings; SQitis possible to assemble and unite the individ-ualgrinding devices; composed of the ringS and the plugs orpinsx14- connected-therewith; with the grind; ing ,tubesections-.1slipped thereon; to form-sets (5", 5", 5'5, 5'! and: so .forthlbymeans-of 'a centrally arranged shaft =64 and a-/ring;- nutf65,;so that a-grinding-roll is produced-,--- thewidth :ofwhich can be adapted tothe surface of the workpiece to be ground. The grinding tube sections-of the 'carrierringfif' (Fig; 24) are, as indicated by-pthe. referencesrfll and 52, displaced,- for. example, thnoughraniangle ofi inrelation to. the position of the grinding ring sectionsi 1', 1' 1""'and 1' (thelast positiomis not shown: inthe-drawing) of the carrier ring 5, so that uniformity is ensured during the grindingoperatlOl'lS-wbklIIflIlS- Of ethe' roll andalso, bythe staggered arrangement, the power consumption shows no unnecessaryfiuctuat-inn zduringtt e grinding-operation- The narrow.-width, .of--..the carrierrings e5 allows anoverlapping. of. .theegrinding ;p aths-.- so that noisteps -or irregularities arerproduced 1011: the surface worked:

By-zthe rapplicationno'f suitable measures,- for example," by;using;a--:mandreltaperingin the axialdirection of the grinding roll or a:conical.-'sleeve; it is possible .to change the efiective: external-:diameterrof the .grindingroll by radi'afly ,shiftingrtheplugs .or. pins 14,-. so. that the diam-: eter of thearollcanabe adaptedto the diameter ofbores; for examplewf tubes. Readjustmenttasthe grinding tube sections; l of theagrinding roll wear :down is also rendered possible by :this means Therabrasivergriticartridges mentionedflin the-description of Fig..aS .can. also :be inserted in thefree apertures in :tlie: grinding rtube sections .-.1 both of the grinding devicetaccording atmFigs. 24 and 25 and also of-that shown in Fig. 12, seeing that unbrokentsurfacesalsorcomeinto qnestionsinathescase Ofiifltfilflflli grindingg-of the? tubes; Thusrnena methods of gginding theqinnerrwall ofstubes-r are; offered; by-the invention.

Finallygit. is also .pointedout thatt thebbndingmaterial. of: the tubular rgrinding bodies man be the-same 'as that. Of". th grinding wheels: which are already known As the endsiof the tube-directedtowardsthesurface towbe... ground :only extendsasmall amount from the carrienand l the tube beaISTOIL. practically its entire length: within..thecarrier", the centrifugal forces producedat the highspeeds. of rotation are takenoup by theucarrieritself, sothat,.in addition to the veryi tightly wound tubes with. plastic bond tubes canalso be used which are produced,ffor examp1e; by saturating withthermosetting synthetic substances into which the abrasiveparticles can also be introduced in the for-nr .ofatube if desired addinga few laps of very strong steel wire fabric, whereupon the bond'is established-by -pressure saturation:

The -factzthat the centrifugal. forces which occur are absorbed by-the carrieralso enables the use of 'the known.

vitrified :bon'ds evenin thecase of tubular grindingbodies of relatively great length. Also in this case, all' thecrossisectional shapesmentioned in-..-the. preceding specification Y can -.beemployed.-. A combination of difierent kinds of bondsn-islikewise-possible. so. that, for example for. reasonsrof:- thertotalt bending strength; the outer tube 1* according to.Fig.;. 5 cube. composed of wound fabric webs bonded with synthetic resin, whereasthe inserted tubularigrindingbodiesSmay have a vitr'ifiedbond.

I claim:

1. Multi-path grindingelements comprising a'plurality' of tubular, 'thimwalled. grinding elements "formed from synthetic.material.saturated,..wound and heavily compressed fabric webs with. abrasivesflembedded" therein;-

said-I grinding ;elements .being. arranged concentrically to oneranother and said grinding elements contactingeach other atfspaced-places-and being fixedly connected to each :other'f at 'said 1 places, .and said grinding elements having a relatively :wide interval between them for 'theremovahof grinding chips.

2.1 Grinding-elementsaas claimed in claim 1 wherein two:tubular grinding elements are concentrically arranged to' each .other" and- 1 ribs .are pressed upon theinterior grindingelement by which said two grinding elements are connected with each other.

3. Grinding elements as claimed .in clainrl whereina plurality of'sma-ller grinding elements are arranged within; :a larger grinding element.

4:1Grinding3elements as.;claimed 'in claim 3 wherein said::smaller grinding elements' are solid.

Referencesfiitedin the file of this patent UNITED STATESWPATENTS 1,437,234" Fraser- Nov. 28', 1922 1,951,977 Hanus- Mar. 20, .1934- 2,000,772 McGill" Mayi'l, 1935 2,290,098 Field July: 14,. 1942 2,439,662 Kidd et 'al. Apr; 13, 1948 2,725,693- Sr'nith' Dec." 6, 1955 FOREIGN PATENTS 271,9i2 Germany June '5; 191-2 5621-128 Germany Nov: 3; 1931 

